BRIEFLY : SAMPRAS' LOSS PUTS NO. 1 RANKING AT RISK.

Byline: Daily News Wire Services

Pete Sampras took a wild-card entry to the Stockholm Open to bolster his top tennis ranking, but it backfired on Wednesday when he lost an opening-round match to Australian Jason Stoltenberg 7-6 (7-5), 4-6, 6-4 at Stockholm, Sweden.

``What went wrong? That's not an easy question to answer,'' Sampras said. ``I had some opportunities I didn't capitalize on. He (Stoltenberg) played some good tennis. I give him credit.''

Sampras will lose 630 points from his No. 1 ranking. That's more than the 605 that separate him from No. 2 Marcelo Rios, who this week is playing a tournament in his home country of Chile.

In a thrilling match that lasted 2 hours, 16 minutes, Sampras fended off seven match points in the final two games.

``I thought it was at least 15,'' quipped a jubilant Stoltenberg, No. 29 in the world and loser of his four previous matches with Sampras. ``I thought it was slipping away at the end. I held on.''

Finally playing without pain, Steffi Graf is one match away from a berth in the season-ending Chase Championships. She beat Mary Joe Fernandez 6-3, 7-6, (7-4) in a first-round match at the Advanta Championships at Villanova, Pa.

When Irina Spirlea lost to fifth-seeded Monica Seles 6-3, 6-4 in a second-round match, it opened the way for Graf to qualify for the elite 16-player Chase tournament in New York next week.

Graf is 17th but would pass Spirlea in the yearlong points race by beating Elena Likhovtseva today.

Last weekend, Graf returned from wrist surgery to capture Leipzig's Sparkassen Cup International in her native Germany.

HOCKEY: Tampa Bay Lightning right wing Mikael Renberg will be out four to six weeks after breaking his left thumb during Tuesday's 10-2 loss to the New York Rangers. Renberg, who plays on the Lightning's top line with center Craig Janney and right wing Wendel Clark, is tied for third among the team's scorers this season with two goals and seven assists in 15 games.

The San Jose Sharks acquired veteran defenseman Jeff Norton from the Florida Panthers for left wing Alex Hicks and a 1999 fifth-round draft pick.

Norton, 32, is in his 12th NHL season and has played for six teams, including the Sharks in the 1993-94 season and part of the next before being traded.

BASKETBALL: Lisa Leslie and Elton Brand have been named USA Basketball's Athletes of the Year after helping lead their respective national teams to gold medals.

Leslie, a member of the Sparks, led the U.S. team at the Women's World Championships in Germany, averaging 17.1 points and 8.8 rebounds per game.

Brand, a forward from Duke University, averaged 17 points and a team-high 7.6 rebounds per game as the U.S. won the gold medal at the Goodwill Games.

HORSE RACING: Awesome Again, winner of Saturday's Breeders' Cup Classic, has been retired to stand at stud at the Kentucky farm of his owner, Frank Stronach.